Patent GB-688230-A (GB)
Title: Improvements in or relating to a method of chemically treating textile materials
IPC: D06B5/00
Filed: 1950-10-11
Abstract: <PICT:0688230/IV (c)/1> <PICT:0688230/IV (c)/2> <PICT:0688230/IV (c)/3> Textile material is chemically treated by passing the chemical in liquid form through a roll of the material which is kept rotating so that the roll is kept full of the treatment chemical.  Figs. 1 and 4 show an apparatus for use in bleaching cotton gauze and similar fabrics.  The unbleached gauze 9, as shown in Fig. 7, is wound upon a foraminated core 10 which has a central perforated section 13 and imperforate end portions, the whole being constructed, for example, of stainless steel.  The roll of material is lowered into vat 1 and provision is made for its rotation about the horizontal axis by an electric motor synchronously driving pulleys 29, 36.  The shaft 18 is hollow so that the treating chemicals may be passed into the roll of material via pipes 34, 31 and holes 14 and shaft 17 may be withdrawn by means of the pressure cylinder 43 so that the roll of material on core 10 may be released or attached to the rotary means.  Tanks 52, 53, 54, 55 are provided for storing the treatment chemicals, they have outlet pipes 56 which are connected via valves 52a-55a by piping 60 to a header 61, which is connected to a discharge outlet 63.  The other end of header 61 is connected via a pump 64 to the inlet pipe 34 of the hollow shaft on which the roll of material is wound in the bleaching vat 1 so that by a system of manually-operated control valves fluid may be passed from a given tank into the interior of the roll of material.  The outlet pipe 49 of the vat 1 is connected to a spout 69 which may be rotated by gearing 58, 70 so that the liquid extracted from vat 1 may be passed into any given one of tanks 52-55 or into sewer pipe 57.  Hence continuous circulation of the fluid in each tank 52-55 may be maintained for any desired period.  The treatment chemicals may be stored in drums which are connected via piping and valves to a measuring chamber and thus into the tanks 52-55.  Cold water is also available at any tank from pipe 92 and a hot water tank which is kept replenished from a heat exchanger and steam pipe 103 is connected to header 61 via pipe 110.  Steam may be blown into the fabric roll from steam pipe 103, branch 114 and T-fitting 32.  Temperature, pressure gauges and flow rate gauges such as 117 are provided.  To bleach a roll of material on core 10 the roll of some 10,000 yards of material is rotated in vat 1 at a slow speed, for example 10 r.p.m., and a desizing solution comprising sulphuric acid and hot water is passed through the roll for about seven minutes at the rate of some 500 gallons/minute.  The supply of desizing solution is then stopped and the reel speed gradually increased to 600 r.p.m. for about one minute and then gradually reduced to 10 r.p.m. again, so that most of the solution is removed from the roll.  A caustic solution at 95-100 DEG  C., comprising sodium hydroxide and sodium silicate is passed through the roll at a rate of some 500 gallons/minute for about ten minutes and the solution supply is then cut-off and the reel spun dry as previously described.  The material is then treated with the desizing solution at a slow speed of rotation and is then washed with warm water.  The bleaching agent which may for example be a mixture of sodium chlorite and hypochlorite is circulated through the reel which is rotating at some 10 r.p.m. for about 16 minutes at a rate of 500 gallons/minute and at a temperature of 35 DEG  C. and the reel is then dried at high speed.  The pH value of the bleach solution remaining in the gauze is then reduced by the circulation of an acid, for example, acetic acid, and water for some six minutes whilst the reel is rotated at 10 r.p.m. and the reel is then spun dry at high speed and then washed for some two minutes in water at low speed and again spun dry.  The roll is then removed from the vat, is unreeled and passed through a tenter for stretching and drying.